Field of the Invention
This invention relates to anti-corrosion agents which are useful for the protection of metal surfaces which come into contact with water-containing hydrocarbons, such as oil/water mixtures obtained during oil-producing operations. More particularly, the invention relates to amino ester and amino amide-ester corrosion inhibitors which are the reaction product of a maleinized polymeric fatty acid, a poly(oxyalkylene)glycol and a nitrogen-containing compound.
Prior Art
Corrosion of metal tubing, casings, pumps and other collection equipment employed in oil-producing operations by petroleum products which contain water is known. Corrosion is particularly pronounced when a substantial quantity of brine containing acidic materials, such as hydrogen sulfide, carbon dioxide and the like, is present in the hydrocarbon oil. In order to protect metal surfaces, it is therefore common practice to add corrosion inhibitors to the petroleum fluid.
The problem has become even more pronounced to recent years due to the increased use of secondary recovery methods which utilize various forms of water flooding. As a result, there is an increasing need for water-soluble corrosion inhibitors. In view of this increased usage and the continual development of new applications where such products are utilized, there is an everincreasing need for new water-soluble corrosion inhibitor products which are effective at low concentrations and are readily obtainable using available processes and reactants.
U.S. Pat. No. 3,985,504 discloses water-soluble anti-corrosive agents which are saponified ene-adducts of maleic anhydride to an unsaturated fatty acid having from 12 to 24 carbon atoms and containing at least one olefinic double bond or derivatives thereof, such as amides or esters. The ene-adducts are saponified with sodium hydroxide, potassium hydroxide, trimethylamine, triethylamine, triisopropylamine, triisobutylamine, triethanolamine or triisopropanolamine to obtain the anti-corrosive agents which are useful in water-containing or aqueous liquids coming into contact with iron or metals containing iron.
U.S. Pat. No. 4,317,740 discloses water-soluble polyesters obtained by condensing a polyoxyalkylene glycol with the addition product of a dimer fatty acid and maleic anhydride. The polyester compositions of U.S. Pat. No. 4,317,740 are employed in aqueous hydraulic systems and exhibit a substantial thickening effect.
Adducts of dimer acid and maleic acid/anhydride are reacted with aliphatic monoamines containing 8 to 22 carbon atoms per molecule and/or esters of monohydric alcohols containing 8 to 22 carbon atoms in U.S. Pat. Nos. 2,902,499 and 2,975,133, however, the resulting corrosion inhibitors are oil-soluble compositions.